1. Field of the Invention
The present invention relates to a method and apparatus for manufacturing a semiconductor device and to a semiconductor device manufactured by the method. Particularly, the present invention relates to a method of manufacturing a semiconductor device including a step of establishing electrical connection between terminal electrodes of a circuit board and electrode pads of a semiconductor substrate by means of ultrasonic vibration, to an apparatus for manufacturing a semiconductor device employing the method, and to a semiconductor device manufactured by the method.
2. Description of the Background Art
Methods of forming a semiconductor device by means of placing a semiconductor substrate on an insulation circuit board have already been known. FIG. 9 is a cross-sectional view for describing one example of such a manufacturing method. According to the manufacturing method shown in FIG. 9, a semiconductor substrate 14 is set on an insulation circuit board 10 such that terminal electrodes 12 of the insulation circuit board 10 oppose electrode pads 16 provided on the semiconductor substrate 14. Connection conductors 18 are bonded to the respective electrode pads 16 of the semiconductor substrate 14 beforehand.
Load is imposed so as to press together a first holding tool 20 for holding the insulation circuit board 10 and a second holding tool 22 for holding the semiconductor substrate 14. Ultrasonic vibration is applied between the first and second holding tools 20 and 22. Consequently, the connection conductors 18 and the terminal electrodes 12 are joined together, thus establishing electrical connection between the terminal electrodes 12 and the electrode pads 16.
Under the conventional method, material of high hardness, such as carbide steel or ceramic, is used for the tool 20 for holding the insulation circuit board 10 and for the tool 22 for holding the semiconductor substrate 14. For this reason, a problem arises such as generation of scratches on the surface of the semiconductor substrate 14 to be mounted by use of the conventional method when ultrasonic vibration is applied to the substrate 14. Such a problem is expected to become more noticeable with an increase in the number or size of semiconductor chips.
The present invention has been conceived to solve such a drawback of the conventional method and is aimed at providing a method of manufacturing a semiconductor device which prevents scratches stemming from ultrasonic vibration, by means of interposing intermediate material of appropriate hardness between a circuit board and a holding tool for holding the circuit board, as well as between a semiconductor substrate and a holding tool for holding the semiconductor substrate.
A second object of the present invention is to provide an apparatus for manufacturing a semiconductor device employing the method.
A third object of the present invention is to provide a semiconductor device manufactured by the method.
The above objects of the present invention are achieved by a method of manufacturing a semiconductor device having a semiconductor substrate mounted on a circuit board. In the method, the semiconductor substrate is mounted on the surface of the circuit board such that terminal electrodes of the circuit board oppose electrode pads of the semiconductor substrate. Electrical connection is established between the terminal electrodes and the electrode pads, by means of applying ultrasonic vibration between a first holding tool for holding the circuit board and a second holding tool for holding the semiconductor substrate. The method further includes at least one of following steps. A step in which intermediate material is interposed between the first holding tool and the circuit board such that the intermediate material adheres to at least one of the first holding tool and the circuit board. A step in which intermediate material is interposed between the second holding tool and the semiconductor substrate such that the intermediate material adheres to at least one of the second holding tool and the semiconductor substrate. The intermediate material interposed between the first holding tool and the circuit board has hardness lower than that of the circuit board. The intermediate material interposed between the second holding tool and the semiconductor substrate has hardness lower than that of the semiconductor substrate.
The above objects of the present invention are achieved by a semiconductor device manufactured by the manufacturing method described above.
The above objects of the present invention are achieved by an apparatus for manufacturing a semiconductor device having a semiconductor substrate mounted on a circuit board. The apparatus includes a first holding tool for holding the circuit board as well as a second holding tool for holding the semiconductor substrate. The apparatus also include a transfer mechanism for transferring the circuit board and the semiconductor substrate between the first and second holding tools such that terminal electrodes of the circuit board oppose electrode pads of the semiconductor substrate. The apparatus further includes a vibration imparting mechanism for imparting ultrasonic vibration between the first holding tool for holding the circuit board and the second holding tool for holding the semiconductor substrate. At least one of intermediate material supply units described below is provided. An intermediate material supply unit for supplying between the first holding tool and the circuit board tape-shaped intermediate material having hardness lower than that of the circuit board. An intermediate material supply unit for supplying between the second holding tool and the semiconductor substrate tape-shaped intermediate material having hardness lower than that of the semiconductor substrate.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.